color overhead in PowerPoint

[Guest]

dear community

kind some one please tell / explain to me about this term use in the
Template Wizard steps:

the step where the wizard enquire how user wants their presentation style to
be and I understand what are the follow:

on-screen
web
slide

but I cannot understand what is meant by

a) color overheads
b) black and white overheads

thanks to all for the kind explanation

 

[Guest]

overheads are the large printed slides used by overhead projectors.
--

 

[Guest]

thanks alot John Wilson, now i understand

thanks community for help